Social communication is at the heart of successful, healthy social interactions in humans. Social communication deficits are characteristic of several mental health disorders, including anxiety, depression, and autism spectrum disorders. Dysfunction in reward neural systems, including opioid neural systems, has been pro- posed to contribute to social communication deficits characteristic of these disorders, yet little research has focused on the role of reward neural systems in social communication. Furthermore, it is not clear why communication deficits associated with these disorders are observed in some but not other social contexts. One possibility supported by pilot data in a songbird model system is that communication in distinct social contexts is rewarded by distinct mechanisms. The long-term goal of the principal investigator is to identify the neurochemical mechanisms responsible for communication produced in distinct social contexts. The objective of this application is to identif the role of reward and opioid neuropeptides in the medial preoptic nucleus (mPOA) in communication in distinct social contexts. The mPOA regulates affiliative social behavior and communication, and opioid release in mPOA induces reward. In a songbird model, sexually-motivated communication (SMC) can result in immediate external reward (e.g., courtship song results in copulation). In contrast, general social communication (GSC) occurs in social groups in a non-sexual, affiliative context and does not result in immediate overt reward (e.g., copulation), suggesting GSC is linked to intrinsic reward. The central hypothesis sup- ported by strong preliminary data is that GSC is stimulated and maintained by an individual's intrinsic reward state induced by opioid release in mPOA. In contrast, SMC may be reinforced primarily by conspecific responses to song. Four specific aims based on strong pilot data in a songbird model system are proposed 1) to determine the extent to which opioid markers in mPOA relate to individual differences in GSC and SMC using Western immunoblots and quantitative real time PCR in starlings singing in distinct social contexts; 2) to determine the extent to which opioid markers in mPOA relate to intrinsic reward associated with GSC and SMC using conditioned place preference, a standard measure of reward; 3) to determine the extent to which opioids stimulate GSC and SMC using site-specific opioid pharmacological manipulations in mPOA; 4) to determine the extent to which opioid antagonists disrupt the link between reward and GSC by examining effects of opioid pharmacological manipulations in mPOA on song-associated reward measured using conditioned place preference. Results will elucidate links between opioids, reward, and communication produced within distinct social contexts. The research is innovative and significant because it will provide novel insight into neural mechanisms underlying the motivation to communicate and ways in which distinct reward mechanisms function to shape socially-appropriate behavioral interactions. Findings will reveal mechanisms that facilitate communication in select social contexts.